package org.apache.velocity.context;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.    
 */

import java.util.HashMap;
import java.util.Stack;
import java.util.List;

import org.apache.velocity.app.event.EventCartridge;
import org.apache.velocity.runtime.resource.Resource;
import org.apache.velocity.util.introspection.IntrospectionCacheData;

/**
 * class to encapsulate the 'stuff' for internal operation of velocity. We use
 * the context as a thread-safe storage : we take advantage of the fact that
 * it's a visitor of sorts to all nodes (that matter) of the AST during init()
 * and render(). Currently, it carries the template name for namespace support,
 * as well as node-local context data introspection caching.
 * 
 * Note that this is not a public class. It is for package access only to keep
 * application code from accessing the internals, as AbstractContext is derived
 * from this.
 * 
 * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
 * @version $Id: InternalContextBase.java 731266 2009-01-04 15:11:20Z byron $
 */
class InternalContextBase implements InternalHousekeepingContext, InternalEventContext {
	// /**
	// * Version Id for serializable
	// */
	// private static final long serialVersionUID = -245905472770843470L;

	/**
	 * cache for node/context specific introspection information
	 */
	private HashMap<Object, IntrospectionCacheData> introspectionCache = new HashMap<>(33);

	/**
	 * Template name stack. The stack top contains the current template name.
	 */
	private Stack<String> templateNameStack = new Stack<>();

	/**
	 * Velocimacro name stack. The stack top contains the current macro name.
	 */
	private Stack<String> macroNameStack = new Stack<>();

	/**
	 * EventCartridge we are to carry. Set by application
	 */
	private EventCartridge eventCartridge = null;

	/**
	 * Current resource - used for carrying encoding and other information down
	 * into the rendering process
	 */
	private Resource currentResource = null;

	/**
	 * List for holding the macro libraries. Contains the macro library template
	 * name as strings.
	 */
	private List macroLibraries = null;

	/**
	 * set the current template name on top of stack
	 * 
	 * @param s
	 *            current template name
	 */
	public void pushCurrentTemplateName(String s) {
		templateNameStack.push(s);
	}

	/**
	 * remove the current template name from stack
	 */
	public void popCurrentTemplateName() {
		templateNameStack.pop();
	}

	/**
	 * get the current template name
	 * 
	 * @return String current template name
	 */
	public String getCurrentTemplateName() {
		if (templateNameStack.empty())
			return "<undef>";
		else
			return (String) templateNameStack.peek();
	}

	/**
	 * get the current template name stack
	 * 
	 * @return Object[] with the template name stack contents.
	 */
	public Object[] getTemplateNameStack() {
		return templateNameStack.toArray();
	}

	/**
	 * set the current macro name on top of stack
	 * 
	 * @param s
	 *            current macro name
	 */
	public void pushCurrentMacroName(String s) {
		macroNameStack.push(s);
	}

	/**
	 * remove the current macro name from stack
	 */
	public void popCurrentMacroName() {
		macroNameStack.pop();
	}

	/**
	 * get the current macro name
	 * 
	 * @return String current macro name
	 */
	public String getCurrentMacroName() {
		if (macroNameStack.empty()) {
			return "<undef>";
		} else {
			return (String) macroNameStack.peek();
		}
	}

	/**
	 * get the current macro call depth
	 * 
	 * @return int current macro call depth
	 */
	public int getCurrentMacroCallDepth() {
		return macroNameStack.size();
	}

	/**
	 * get the current macro name stack
	 * 
	 * @return Object[] with the macro name stack contents.
	 */
	public Object[] getMacroNameStack() {
		return macroNameStack.toArray();
	}

	/**
	 * returns an IntrospectionCache Data (@see IntrospectionCacheData) object
	 * if exists for the key
	 * 
	 * @param key
	 *            key to find in cache
	 * @return cache object
	 */
	public IntrospectionCacheData icacheGet(Object key) {
		return (IntrospectionCacheData) introspectionCache.get(key);
	}

	/**
	 * places an IntrospectionCache Data (@see IntrospectionCacheData) element
	 * in the cache for specified key
	 * 
	 * @param key
	 *            key
	 * @param o
	 *            IntrospectionCacheData object to place in cache
	 */
	public void icachePut(Object key, IntrospectionCacheData o) {
		introspectionCache.put(key, o);
	}

	/**
	 * @see org.apache.velocity.context.InternalHousekeepingContext#setCurrentResource(org.apache.velocity.runtime.resource.Resource)
	 */
	public void setCurrentResource(Resource r) {
		currentResource = r;
	}

	/**
	 * @see org.apache.velocity.context.InternalHousekeepingContext#getCurrentResource()
	 */
	public Resource getCurrentResource() {
		return currentResource;
	}

	/**
	 * @see org.apache.velocity.context.InternalHousekeepingContext#setMacroLibraries(List)
	 */
	public void setMacroLibraries(List macroLibraries) {
		this.macroLibraries = macroLibraries;
	}

	/**
	 * @see org.apache.velocity.context.InternalHousekeepingContext#getMacroLibraries()
	 */
	public List getMacroLibraries() {
		return macroLibraries;
	}

	/**
	 * @see org.apache.velocity.context.InternalEventContext#attachEventCartridge(org.apache.velocity.app.event.EventCartridge)
	 */
	public EventCartridge attachEventCartridge(EventCartridge ec) {
		EventCartridge temp = eventCartridge;

		eventCartridge = ec;

		return temp;
	}

	/**
	 * @see org.apache.velocity.context.InternalEventContext#getEventCartridge()
	 */
	public EventCartridge getEventCartridge() {
		return eventCartridge;
	}
}
